Whether the principle of \’Res Judicata\’ operates between co-plaintiffs or co-defendants?

It has been held by Hon\’ble Apex Court in the case of \”Iftikhar Anmed v. Syed Meharban Ali\” (reported in AIR 1974 SC 749] that…

The rule of res judicata while founded on ancient precedent is dictated by a wisdom and the application of the rule should be influenced by no technical considerations of form, but by matter of substance within the limits allowed by law. The raison d\’etre of the rule is to confer finality on decisions arrived at by competent Courts between interested parties after genuine contest.

\”It is now settled that for a judgment to operate as res judicata between or among co-defendants, it is necessary to establish that

(1) there was a conflict of interest between the co-defendants

(2) that it was necessary to decide the conflict in order to give relief which the plaintiff claimed; and

(3) that the Court actually decided the question. If thus a previous decision can operate as res judicata between the co-defendants under certain conditions, there is no reason why a previous decision should not operate as res judicata between the co-plaintiffs if the same conditions are mutatis mutandis satisfied.\”